Whether you’re floating around Europe for a couple of months or trekking through Asia, your most important piece of equipment will of course be your backpack. It’ll be your constant companion, your lifeline, and it will protect and carry all of the rest of your belongings for the extent of your journey. That’s why it’s important that you pick the right one, and have an idea of what you need before you buy.

Backpacks essentially come in two design types, internal and external frame. Most modern designs are of the internal frame variety, which offers the most flexibility and versatility of use. In fact, it’s rather difficult to find external frame packs any more, and for the sake of travel, they are not all that desirable. They don’t stow away as neatly, and they don’t fit in over head compartments as nicely either.

Knowing that you’ll most likely be purchasing an internal frame pack, the next thing to think about is size. Packs really do come in a wide variety of sizes now days, and the size you’ll need really depends on the length of your trip. For an extended journey you’ll be looking for an expedition length pack or a pack that is in the 5000 – 6000 cubic inch capacity. Remember, it’ll be holding all of your clothing and other gear, such as a sleeping bag, possibly a tent, cooking equipment, and more. Bigger isn’t always better however, so don’t just rush out and buy the biggest bag you can find.Armed with this information, the next thing you’ll want to do is go to an outdoor store and try on some of the bags. Any reputable gear reseller, such as REI, should have someone on staff who can measure your torso and help fit your properly with the right pack. It’s essential that you get the proper fitting, which is why I generally don’t recommend that you order a pack off the Internet without first having tried it on. If you do decide to order online, Backcountry.com and Eastern Mountain Sports often have great deals on packs.

It’s likely that you may be a bit overwhelmed with the dizzying array of backpacks that are now available. There are dozens of companies, making hundreds of different packs, and in a larger store you could have far more of them to choose from than you ever thought possible. However, knowing the size and style that you want will help whittle the selection down quickly, as will having your torso measured. From there, it’s a matter of finding a pack that has all the options you want and fits comfortably.

The level of comfort when you are wearing the pack is the single most important factor when deciding what to buy. When measured properly and adjusted for your body, something the staff at the store can help with as well, the pack’s weight should rest mostly on your hips. A good outdoor store will fill your pack with some weight to simulate what it’ll be like when you have it full of gear. This will help you to determine if the pack will be comfortable over the course of long days and carrying heavy loads. Try on as many packs as it takes to find the one that is most comfortable to you personally and fits your body the best.

The gear companies have come up with a ton of options for backpacks as well, some are gimmicks, and some are real. They put pockets in all kinds of locations, and they design special suspension systems to make the load more comfortable. The one option that I recommend that you absolutely do not go without is that your pack is “hydration ready”. That means that it has a special pocket that allows you to slip in a hydration bladder, a plastic reservoir that holds liquids, allowing you to carry your water easily. A small tube from the bladder will extend out of the pack and over your shoulder, connecting to one of the straps, and making it easy for you to take a drink at any time. The usefulness of this feature can not be over stressed, but it’s also common in most packs these days, so almost anything you buy will be hydration ready.

It should also be noted that most gear manufacturers now make women specific packs. This was not always the case and in the past ladies were often forced to endure a bag that didn’t fit well nor allow them to carry their gear comfortably. Now there are plenty of packs, in all sizes, that are designed to fit the female form, providing more comfort for extended time on the trail. They even come in more feminine colors so the girls won’t feel embarrassed to be seen wearing them. The Deva line of packs from Gregory are excellent as are the Aura packs from Osprey.

The last thing to consider is price. Go in with an idea of how much you want to spend ahead of time, as these days there are backpacks for all budgets. You can spend as little as $100 and get a decent backpack, or as much as $500+ and get an amazing piece of gear. But not everyone needs the top of the line item, and the packs found at the lower end of the spectrum these can be really good, although they tend to lag behind the higher end gear in features and fit by a few years. High Sierra has made a name for itself with it’s high quality packs at reasonable prices. Obviously price is an important consideration, but I wouldn’t recommend trying to save a few dollars at the expense of comfort. If spending a bit more gets you a noticeably better fit, then it’s worth dropping the dough. I personally own packs from The North Face, Osprey, and Mountain Hardwear, and while a bit more expensive, they are definitely worth the money.

Remember, buying a backpack is a major investment in your travel gear, but if you buy a good one, it can last you for years. You’ll can take it with you on your travels no matter where they lead, and you’ll come to realize that it really is the most important piece of gear you’ve ever purchased.